The experimental evidence supporting the real existence of light quanta derived based on wave theory, are discussed. It is assumed that all light quanta are identical and only their velocities are different. The frequency of the corresponding radiation must be related to the whole energy of a quantum by the relation. The light quanta would have velocities of slightly different values, but they cannot be discriminated from limiting velocity by any experimental means. The light quantum must have an internal binary symmetry corresponding to the symmetry of an electromagnetic wave and defines by some axis of polarization. The phase wave has a constant frequency v and a constantly variable velocity V during light propagation.